On the whole, doctors will tell you that exercise is good for you.  And it is!  In fact, studies have shown that sports have a beneficial effect on cartilage, even regular intense vigorous sports. Cartilage is nourished by activity, and sports can help to maintain healthy cartilage.   But with some sports there is a high risk of joint injury – and it is this recurrent injury which over time can wear out your joints or cause permanent damage.  So, the bottom line is that if you engage in vigorous intense activities, as long as you do stuff to protect your joints and reduce the risk of injury, your joints should be fine.  For instance, if you’re a keen runner – don’t stop running; instead invest in a good pair of running shoes with good shock absorption.

The Research

• A study at Stanford Univeristy in 2008 looked at 1000 runners over 20+ years and found no difference between the knees of runners and non-runners.  And it didn’t seem to matter how much the runners ran.  Their joints were just the same!  However, the runners had a 40% lower death rate than non-runners. (Archives of Internal Medicine, 2008)
• In 2007, an American study showed that over 9 years, active elderly people had the same risk of arthritis as the least active.  In other words, exercise and activity does not accelerate wear and tear.
• In 2007, Australian researches concluded that people who exercised vigorously had thicker and healthier knee cartilage than their sedentary peers.  So, it seems that if you don’t exercise much, the more your cartilage in your knees is likely to breakdown and lose strength.   (Arthritis and Rheumatism, 2007).   How do we explain this?   Unlike other parts of your body, the cartilage does not have arteries that deliver blood and nutrients to it.  Instead, it gets its nutrients through a pumping action; as you weight bear, fluid in the cartilage is squeezed out, and as you relax, fluid with more nutrients is sucked back in.   So, if you are fit and active, the more your cartilage is likely to be nourished.
• A large study in Medicine & Science in Sports & Exercise concluded that running does not increase osteoarthritis.  Runners action had HALF the incidence of knee osteoarthritis compared to walkers!  Running can thicken the cartilage in your knee.

So, in summary

• All sports are okay.
• Some sports have a higher risk of injury than others.   Do something to protect yourself from that injury as much as possible.  It is that injury that will cause problems in the future.
• Aggressive intense sports are not necessarily bad for you.   It’s not the aggressive sport that’s the problem – it’s the sudden plunge into that activity that increases the risk of injury – therefore, if you’ve been lazy bones for a while and want to get fit, get back into it gradually.  And again, think about what other protective measures you can put into place to reduce the risk of injury.
• Also, think about balancing your activities – a selection of weight-bearing and non-weight-bearing activities – so running and cycling, or running and the cross-trainer (especially if you are age 40 or over).  (PS running is weight-bearing, cycling and cross-trainer are not).
• All sports will help you to lose weight and keep fit.
• The person who is active and fit and moving around is doing the most active defense against arthritis. In addition, they will be doing the most in terms of preventing their bones from becoming weaker with age (a condition called osteoporosis – which is very common in the US and the UK).
• The more fit you are, the longer you are more likely to live.  In fact, a study has shown that people who are active well into their elder years may be in a better state of health than people 40-50 years YOUNGER than them!   The study was done on senior skiers!  The more vigorous the activity, the more fitness capacity you will develop.  Vigorous activity helps you to live longer.
• And finally, listen to your body.  It is telling you to stop, rest, reflect on the situation and seek professional advice (physio, doctor, sports trainer).

In particular: how to protect your knees

• Simple – work on the buttock muscles (the gluteals) and the muscles at the front of the thigh (the quadriceps).
• Exercises like the straight-leg raise, clamshell, bridge and squats.   More on these here….
• Back off from running until you strengthen these muscles.
• If you are already experiencing knee pain, stiffness, locking or giving way/instability – again, BACK OFF from running and go and see your GP.

So what does cause osteoarthritis if it is not exercise?

• There are genetic factors.   In other words, if there are two or more family members who developed early osteoarthritis (in their 40s, 50s or 60s), then there is a higher chance that you will get it too.  If this is the case, all is not lost – think about what you can do to reduce the risk of arthritis.   For instance, running may not be the best exercise for you because of the weight impact on the knees.  Perhaps something easier on the knees like the cross trainer or cycling.  Remember, there are always things you can still do.
• If you are overweight, that has a big influence.  Listen to this: obese men and women are FOUR TIMES as likely to become arthritic as their thinner peers!
• Get your feet checked by a professional.   Some people have flat feet or feet that generally don’t sit well on the floor (called ‘excessive pronators’).  This means additional pressure is put on the other joints like the hips, knees and back, and their shock absorption mechanism isn’t as powerful.  Ultimately, this leads to pain and wear in those areas.  You may simply need to some show inserts to ‘lift up’ the inner part of your feet.  But don’t just go out there and buy some – get your feet assessed by a physiotherapist or podiatrist first.
• And if you are the type of person who has super flexible joints (for example, you can easily bend your thumb backwards), then you are at higher risk of arthritis because your extra bendability in your joints means your body doesn’t have the protective mechanism that other people with normal flexibility have.  Go and talk to your doctor or physiotherapist about this – even if you don’t have pain now and your joints feel fine – because you need to make sure you don’t set them up for developing arthritis later on.   People with hyperextending knees (called genu recurvatum) often have trouble even running a mile or two.

Which sports are at high risk of causing joint injury

• Soccer – Football is one of the most riskiest sports because there’s always someone who injures their knee or ankle during a tackle.  And these injuries can be significant and have long term consequences.
• Basketball – a good exercise that works your heart and lungs.  The downside is the high rate of injury from sudden stops, starts, twists and turns – harsh on the knees and the back.  But it doesn’t have to be high risk of injury if you’re just having gentle fun with friends (as opposed to being seriously competetive).
• Jumping sports – again – you need to protect the knees.  These can be very harsh on the knees.
• Ski-ing – again, protect the knees.   There’s always someone who twists their knee and when that happens, the injury is often permanent!
• Squash – Squash can be hard on the joints.  If you twist on your knee – you can injure the cruciate ligaments which are important in knee stability.  So, be careful in sudden harsh knee bends. Squash players also tend to get patello-femoral arthritics (which is a bit like patello-femoral syndrome except that the cause is more permanent and more difficult to treat).  Going slightly off the topic, don’t forget to wear squash goggles to protect your eyes.  The squash ball is almost exactly the same size as your eyeball and a hard return can result in the loss of an eye.  Also be wary of groin pulls, torn Achilles tendons and, of course, your opponent’s racquet!   If you have weak muscles, you are  more likely to injure yourself.  To reduce the risk of injury – consider yoga for flexibility, sprinting and distance running for muscle building on top of the squash.
• Cycling outside – Cycling is a fab exercise because it is non-weight bearing and aerobic.  But it has one of the highest rates of injury as people come off their bikes!  Also, it doesn’t do much for flexibility or upper body strength – so do something to work on these. If you are scared about cycling because you haven’t done it for years and worried about the roads and traffic, there will always be a ‘start cycling’ course near you, often free, to help you get back into it.  For instance, if you’re in West Yorkshire, the Go Cycling team are fab.
• Running – invest in a good pair of shoes and learn how to run smart – slowly build up your endurance, perhaps even start with walking first.  For example, if you have a smartphone, use ‘Couch Potato to 5K’ – an app version is available on itunes.   Also think about getting professionally assessed in the way you run (by a physiotherapist) who will tell you if your stride is too big, how you lift your foot off the ground and whether you strike the ground to hard.   Over time, there is a risk of stress fractures (also called hairline fractures – tiny cracks usually in the shin bone (tibia) which develop over time); these result in shin splints or shin pain.  If this happens to you, go see a physiotherapist.  And make sure that you do not engage in the activity for at least four weeks to help the tiny fractures to heal.  You will need to GRADUALLY work on strengthening some of the  calf muscles like rising up on your toes about a dozen times a day.   Stronger muscles ultimately make stronger bones. And when you go back to running, think about reducing the length of your running stride by about 10% (can reduce the risk of future fractures by 30%) whilst maintaining your usual pace.    There’s also the dreaded ‘IT band syndrome’ where the iliotibial band becomes too tight.  On the whole – don’t be put off by running – people who claim that running caused their knee pain often already had had injured knees because they didn’t protect them in the first place.
• Long walks on rough terrain – if you do regular long walks (6-8 miles) on rough terrain, then you could be wearing your knee joints as a result of all the impact and small twists and turns.   So, invest in some good boots and buy a pair of walking sticks (and learn how to use them – there is a specific way).

In all of these activities, work on your quads!  One study revealed that a relatively small increase in quadriceps strength (20%–25%) can lead to a 20%–30% decrease in the chance of developing knee osteoarthritis. Aim for a minimum of 30 minutes of exercise on most days of the week.

Which sports are less risky for injury

• Walking on the flat – has generally less impact on the knees than walking on rough terrain.  And walking on grass is even better.
• Cycling at the gym – good for aerobic fitness and good on the joints.   But it doesn’t do much for flexibility or upper body strength – so do something to work on these.
• Rowing machine – a good all round activity with minimal risk of injury.
• Swimming – another good all round activity.    Get an instructor to check your technique.   To maximise benefits, do interval training – swim two lengths then a break to catch your breath for 1 minute.  Repeat.   To supplement, consider core exercises, weight training, and yoga to maintain body alignment and awareness.
• Cross trainer machine – good total body workout.   Good for thighs, back and shoulders.
• Using gym equipment
• Weight lifting – but don’t over do yourself.
• Badminton and tennis – less riskier than squash.

A table to compare sports activities

Activity	Cardio-Resp	Muscle strength	Muscle endurance	Flexibility	Calories in 30 mins	Injury risk
Squash	v. high	Medium	V high	Medium	500	High
Basketball	High	Medium	V high	High	300	High
Running	V high	Medium	High	Low	400	Moderate-High
Boxing	Medium	Medium	V high	Low	300	Moderate
Cycling outdoors	V high	Medium	V high	Low	400	high
Cycling at the gym	V high	Medium	V high	Low	400	Low
Rowing machine	V high	High	V high	Medium	300	Low
Swimming	High	Medium	V high	Medium	350	Low
Cross trainer machine	V high	Medium	V high	Medium	350	Low

A reminder of what health is…

• Being healthy is about reducing the risk of future disease (like heart attacks, strokes, arthritis and so on).

A reminder of what fitness is…

To be fit means maximising on the 4 physiological components of fitnesss

1. cardio-respiratory endurance (i.e. aerobic activity e.g. running)
2. muscular strength (e.g. weight training)
3. muscular endurance (e.g. through weight training or building up on aerobic activity)
4. flexibility (stretching exercises eg yoga, pilates, stretch exercises in general)

Closing statement

Of course, one can be healthy without being fit, and vice versa. But while the out-of-shape middle managers you see huffing and puffing toward the departure gate may be able to reach their life expectancy, they’re going to be a lot less comfortable getting there than those who strive to maintain peak physical condition along the way.